Beginner Vegetables: Matina Tomato plant problem?!

Hi everyone,
I have about 20 matina tomato plants I've grown from seed using soil pods and transplanted to larger pots almost a week ago. They have no moved from the window (have rotated every other day) since I started them. I have about 75 plants in total there and today I noticed this plant and the surrounding soil has a white cotton-y appearance sitting on top of it. I watered them all two days ago and they've all been fine except for this single plant. Usually I water every single day - just a little bit - and then they are dry the next day so maybe I overwatered a bit the other day? I have added a photo of another matina plant of mine for comparison.

its looks like the normal white stuff on soil when you have them indoors, i wouldnt worry about it as long as its not growing directly on the plant. it should die away over time. i usually see this too and only when the soil surface is somewhat dry. since they are indoors, be careful not to keep the soil soggy, just moist. hope this helps

Ditto what Costal said. It happens all the time when you start seeds indoors. Most seedlings are not effected by it. Easing up on watering sometimes helps, but usually moving the seedlings outside into full sun at transplant is what finally takes care of the fungi.

I grow 1000s of seedlings every year and I see that alot. I don't notice it when the soil is wet only when the surface dries. If you haven't done this already you may want to put a fan near the seedlings. Not only does it help to make the stems stockier it also keeps the air circulating which is a big + when growing your own plants.

Kinda looks more like that one's mold, like on wet soil, not like the white stuff you can see on good watered , but dry soil. It's a bit hard to see on the pic though. Maybe go easy on the watering on the white stuff and see what happens. Maybe carefully remove the top layer where you can see the stuffy stuff.

If the plants don't wilt much, they might be happier if you watered less often.

If the mix is fast-draining enough that it lets air back in after heavy watering, the roots will be happier with watering INfrequently, heavy enough to let water come out the bottom, and then no more water until the soil is drying out several inches deep. It might even be smart to watch for the first plant start to wilt, and then water just slightly more often.

Frequent misting is for keeping seeds moist until they germinate and emerge - not so good for plants after they've emerged.

But if your soil mix is peaty and fine-grained, never soak it completly because you'll drive all the air out of then soil, and roots may drown beofre they can drink up enouigh to let some air back in.

In that case, or if frequent light wtaerings are keeping the deeper soil too wet, it might help roots breath if you sit the pots on a piece of cotton (flannel, towel, Tee shirt, anyh old rag that's absorbant). When the soil touches the towel through holes in the bottom of the pot, capilary action will encourage some water to drain out olf your peaty mix, and hopefully let air bac intol the soil. Roots will breath a sigh of relief!

Letting the surface dry out between waterings should reduce the risk of mold.